Cut each chicken breast in half longways so you have 2 fillets from each breast. Pound with a meat tenderizer until each breast is about ¼” thick.
Lay a piece of prosciutto on each piece of chicken breast to cover the top. Then, lay 2 sage leaves on top of each piece of prosciutto and secure the prosciutto slice and sage leaves onto the chicken with toothpicks then set aside.
In a small shallow bowl or plate, mix together the all purpose flour, salt and pepper. Press each piece of chicken into the flour with the side that does not have the prosciutto and sage on it. Save the excess seasoned flour for later.
Heat oil in a large skillet over medium heat. Place the chicken in the skillet with the sage and prosciutto side facing down.
Cook for 5-6 minutes, flip so the floured side is facing down and cook for another 3-4 minutes. Remove the chicken from the skillet when the internal temperature reaches 165F. Set to the side on a plate or cutting board.
Turn skillet heat to low and add the butter to the pan. When the butter is fully melted, add 2 tbsp of the flour mixture you used earlier to the pan and whisk to fully mix into the butter like a paste. Slowly pour the white wine into the pan, whisking constantly as you pour until a smooth sauce remains.
Increase the heat to medium and allow the mixture to simmer for 5 minutes. Add the chicken back into the pan and nestle it into the sauce with the prosciutto side up. Allow the chicken to rewarm for a minute in the sauce and then serve. I like to serve over pasta or roasted potatoes and use any extra wine sauce over the dish.
Notes
Slice the chicken thin so it cooks fast and evenly.
Do not overcrowd the pan. You want to make sure each piece of chicken gets a nice sear.
Make sure your wine is dry for this recipe. Sweet wines will change the flavor of the dish and make it too sweet.